Ray propagation in nonuniform random lattices. Part II

In this paper and its companion [J. Opt. Soc. Am. A.23, 2251 (2006)], the problem of ray propagation in nonuniform random half-plane lattices is considered. Cells can be independently occupied according to a density profile that depends on the lattice depth. An electromagnetic source external to the lattice radiates a monochromatic plane wave that undergoes specular reflections on the occupied sites. The probability of penetrating up to level k inside the lattice is analytically evaluated using two different approaches, the former applying the theory of Markov chains (Markov approach) and the latter using the theory of Martingale random processes (Martingale approach). The full theory concerned with the Martingale approach is presented here, along with an innovative modification that leads to some improved results. Numerical validation shows that it outperforms the Markov approach when dealing with ray propagation in dense lattices described by a slowly varying density profile.     

Identification of cocaine and its metabolites in urban wastewater and comparison with the human excretion profile in urine

The most relevant human urinary metabolites of cocaine (nine metabolites) were measured in urban wastewater in Italy and USA. A novel analytical method based on liquid chromatography tandem mass spectrometry allowed the identification of ecgonine, ecgonine methyl ester and the pyrolytic derivatives of cocaine in untreated wastewater. The aim of this study was to verify whether the pattern of cocaine metabolites in wastewater reflected the human excretion profile in urine. The performance of the method was good, with recoveries higher than 60% and limits of quantifications in the low ng/L range. The stability in untreated wastewater was assessed for all metabolites and the best storage condition resulted freezing samples immediately after collection and keep them frozen until analysis. All the selected compounds were measured in wastewater at concentrations up to 1.5 μg/L and their weekly loads were calculated during a five weeks monitoring campaign in Milan (Italy). The profiles of cocaine metabolites in wastewater matched with those in human urine reported in the literature, suggesting that measures in wastewater reflect the real human excretion and that wastewater analysis is suitable for assessing drug consumption. Benzoylecgonine was confirmed as the best target for estimating cocaine use by wastewater analysis, while cocaine itself should not be considered because its amount in wastewater is affected by other environmental sources such as transport, handling and consumption. Results suggested that the measurement of other metabolites in combination with benzoylecgonine might reflect 60% of an administered dose of cocaine providing also information on different patterns of use.     

1H low- and high-field NMR study of the effects of plasma treatment on the oil and water fractions in crude heavy oil

The chemical and physical properties of a Brazilian heavy oil submitted to plasma treatment were investigated by ¹H low- and high-field nuclear magnetic resonance (NMR) combined to the characterization of rheological properties, thermogravimetry and measurement of basic sediments and water (BSW) content. The crude oil was treated in a dielectric barrier discharge plasma reactor, using natural gas, CO₂ or H₂ as working gas. The results indicated a large drop in the water content of the plasma-treated samples as compared to the crude oil, giving rise to a reduction in the viscosity. No significant chemical change was produced in the oil portion itself, as observed by ¹H NMR. The water contents determined by ¹H low-field NMR analyses agreed well with those obtained by BSW, indicating the low-field NMR methods as a useful tool for following the effects of plasma treatments on heavy oils, allowing the separation of the effects caused on the water and oil fractions.     

Photodegradation of copolyester films: A mechanistic study

The photodegradation of copolyesters based on 1,4-cyclohexanedimethanol (CHDM), tetramethyl-1,3-cyclobutanediol, and terephthalic acid units was investigated using various analytical methods. Photodegradation products were characterized using Fourier transform infrared (FTIR), liquid chromatography–mass spectrometry (LC–MS), and X-ray Photoelectron spectroscopy (XPS) analysis. The homolytic scission of C-O bonds of ester groups through a Norrish Type I reaction was supported by time of flight secondary ion mass spectrometry and LC–MS results, while nuclear magnetic resonance analysis confirmed hydrogen abstraction from the tertiary carbon of CHDM units in the trans (equatorial-equatorial) conformation. Chain scission through Norrish Type II reaction is also responsible for the formation of carboxylic acid end group. Fluorescence emission from irradiated glycol modified poly(ethylene terephthalate) films demonstrated the formation of mono- and dihydroxyterephthalate species. Furthermore, FTIR and XPS valence band analysis confirmed configurational changes, in the polymer chain due to photodegradation. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47148.     

Quality, safety and sustainability in food distribution: a review of quantitative operations management approaches and challenges

The management of food distribution networks is receiving more and more attention, both in practice and in the scientific literature. In this paper, we review quantitative operations management approaches to food distribution management, and relate this to challenges faced by the industry. Here, our main focus is on three aspects: food quality, food safety, and sustainability. We discuss the literature on three decision levels: strategic network design, tactical network planning, and operational transportation planning. For each of these, we survey the research contributions, discuss the state of the art, and identify challenges for future research.     

Ovarian Cancer Cells in Ascites Form Aggregates That Display a Hybrid Epithelial-Mesenchymal Phenotype and Allows Survival and Proliferation of Metastasizing Cells

Peritoneal metastases are the leading cause of morbidity and mortality in ovarian cancer. Cancer cells float in peritoneal fluid, named ascites, together with a definitely higher number of non neo-neoplastic cells, as single cells or multicellular aggregates. The aim of this work is to uncover the features that make these aggregates the metastasizing units. Immunofluorescence revealed that aggregates are made almost exclusively of ovarian cancer cells expressing the specific nuclear PAX8 protein. The same cells expressed epithelial and mesenchymal markers, such as EPCAM and αSMA, respectively. Expression of fibronectin further supported a hybrid epithelia-mesenchymal phenotype, that is maintained when aggregates are cultivated and proliferate. Hematopoietic cells as well as macrophages are negligible in the aggregates, while abundant in the ascitic fluid confirming their prominent role in establishing an eco-system necessary for the survival of ovarian cancer cells. Using ovarian cancer cell lines, we show that cells forming 3D structures neo-expressed thoroughly fibronectin and αSMA. Functional assays showed that αSMA and fibronectin are necessary for the compaction and survival of 3D structures. Altogether these data show that metastasizing units display a hybrid phenotype that allows maintenance of the 3D structures and the plasticity necessary for implant and seeding into peritoneal lining.     

Avoiding cross-bifix-free binary words

In this paper we study the construction and the enumeration of binary words in $\{0,1\}^*$ having more 1’s than 0’s and avoiding a set of cross-bifix-free patterns. We give a particular succession rule, called jumping and marked succession rule, which describes the growth of such words according to their number of ones. Moreover, the problem of associating a word to a path in the generating tree obtained by the succession rule is solved by introducing an algorithm which constructs all binary words having more 1’s than 0’s and then kills those containing the forbidden patterns. Finally, we give the generating function of such words according to the number of ones.     

Long-term results from MOPPEBVCAD chemotherapy with optional limited radiotherapy in advanced Hodgkin's disease

The purpose was to verify the 5-year results of the MOPPEBVCAD chemotherapy regimen with limited radiotherapy in relation to the promising preliminary data. Mechlorethamine, vincristine, procarbazine, prednisone, epidoxorubicin, bleomycin, vinblastine, lomustine, melphalan, and vindesine were delivered according to a schedule derived through hybridization, intensification, and shortening of the corresponding alternating CAD/MOPP/ABV regimen. Radiotherapy was restricted to sites of bulky involvement or to areas that responded incompletely to chemotherapy. This multicenter, controlled, nonrandomized trial involved 145 eligible patients. Radiotherapy was administered to 47 patients, 46 of whom were in complete remission after chemotherapy. Remissions were complete in 137 patients (94%), partial in 4 (3%), and null in the remaining 4. Tumor-specific, overall, relapse-free, and failure-free survival at 5 years were 0.89, 0.86, 0.82, and 0.78, respectively. Hematologic toxicity was considerable, whereas nonhematologic side effects were fully acceptable. Most of the unfavorable prognostic factors lost their clinical weight. Only age and lymphocyte depletion histologic type were statistically correlated with major follow-up endpoints; performance status and bone marrow involvement were subordinate to age. Seven patients developed a second cancer (including 3 myelodysplasias). MOPPEBVCAD with selected radiotherapy is a highly effective regimen in advanced Hodgkin's disease. Early and late toxicity are no more severe than what would be expected with other alternating or hybrid regimens. A comparison with ABVD, which is currently considered the standard regimen for advanced Hodgkin's disease, is needed.     

Dual-phase steel rebars for high-ductile r.c. structures, Part 1: Microstructural and mechanical characterization of steel rebars

The considerable influence of steel’s mechanical behaviour on the dissipative capacity of r.c. structures has led to increasing interest in optimizing the mechanical properties of the reinforcing bars used for seismic applications.

The work presented herein is part of a broad-ranging study on the potential utilization of highly innovative types of steel for reinforced concrete earthquake-resistant structures. In particular, we present the main results obtained in experimental trials on a low-C, Mn–Si steel in the form of concrete reinforcing bars subjected to intercritical tempering treatment in a temperature range between 740 and 820 C to obtain various dual-phase ferrite–martensite structures. The samples were characterized via mechanical tests and metallographic analyses in order to correlate the bars’ characteristics with the microstructure of the steel itself.

Experimental characterization of this steel has allowed for the development of a mathematical model to enable the evaluation of the ductility performance of concrete structural elements reinforced with dual-phase steel bars.